c6d6367f84
Reviewed-on: https://go-review.googlesource.com/87897 From-SVN: r256794
348 lines
9.6 KiB
Go
348 lines
9.6 KiB
Go
// Copyright 2009 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// +build aix darwin dragonfly freebsd linux nacl netbsd openbsd solaris
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package os
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import (
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"internal/poll"
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"runtime"
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"syscall"
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)
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// fixLongPath is a noop on non-Windows platforms.
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func fixLongPath(path string) string {
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return path
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}
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func rename(oldname, newname string) error {
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fi, err := Lstat(newname)
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if err == nil && fi.IsDir() {
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// There are two independent errors this function can return:
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// one for a bad oldname, and one for a bad newname.
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// At this point we've determined the newname is bad.
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// But just in case oldname is also bad, prioritize returning
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// the oldname error because that's what we did historically.
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if _, err := Lstat(oldname); err != nil {
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if pe, ok := err.(*PathError); ok {
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err = pe.Err
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}
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return &LinkError{"rename", oldname, newname, err}
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}
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return &LinkError{"rename", oldname, newname, syscall.EEXIST}
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}
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err = syscall.Rename(oldname, newname)
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if err != nil {
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return &LinkError{"rename", oldname, newname, err}
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}
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return nil
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}
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// file is the real representation of *File.
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// The extra level of indirection ensures that no clients of os
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// can overwrite this data, which could cause the finalizer
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// to close the wrong file descriptor.
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type file struct {
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pfd poll.FD
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name string
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dirinfo *dirInfo // nil unless directory being read
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nonblock bool // whether we set nonblocking mode
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stdoutOrErr bool // whether this is stdout or stderr
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}
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// Fd returns the integer Unix file descriptor referencing the open file.
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// The file descriptor is valid only until f.Close is called or f is garbage collected.
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// On Unix systems this will cause the SetDeadline methods to stop working.
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func (f *File) Fd() uintptr {
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if f == nil {
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return ^(uintptr(0))
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}
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// If we put the file descriptor into nonblocking mode,
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// then set it to blocking mode before we return it,
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// because historically we have always returned a descriptor
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// opened in blocking mode. The File will continue to work,
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// but any blocking operation will tie up a thread.
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if f.nonblock {
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f.pfd.SetBlocking()
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}
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return uintptr(f.pfd.Sysfd)
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}
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// NewFile returns a new File with the given file descriptor and
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// name. The returned value will be nil if fd is not a valid file
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// descriptor.
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func NewFile(fd uintptr, name string) *File {
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return newFile(fd, name, kindNewFile)
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}
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// newFileKind describes the kind of file to newFile.
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type newFileKind int
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const (
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kindNewFile newFileKind = iota
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kindOpenFile
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kindPipe
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)
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// newFile is like NewFile, but if called from OpenFile or Pipe
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// (as passed in the kind parameter) it tries to add the file to
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// the runtime poller.
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func newFile(fd uintptr, name string, kind newFileKind) *File {
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fdi := int(fd)
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if fdi < 0 {
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return nil
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}
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f := &File{&file{
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pfd: poll.FD{
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Sysfd: fdi,
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IsStream: true,
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ZeroReadIsEOF: true,
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},
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name: name,
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stdoutOrErr: fdi == 1 || fdi == 2,
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}}
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// Don't try to use kqueue with regular files on FreeBSD.
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// It crashes the system unpredictably while running all.bash.
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// Issue 19093.
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if runtime.GOOS == "freebsd" && kind == kindOpenFile {
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kind = kindNewFile
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}
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pollable := kind == kindOpenFile || kind == kindPipe
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if err := f.pfd.Init("file", pollable); err != nil {
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// An error here indicates a failure to register
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// with the netpoll system. That can happen for
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// a file descriptor that is not supported by
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// epoll/kqueue; for example, disk files on
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// GNU/Linux systems. We assume that any real error
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// will show up in later I/O.
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} else if pollable {
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// We successfully registered with netpoll, so put
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// the file into nonblocking mode.
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if err := syscall.SetNonblock(fdi, true); err == nil {
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f.nonblock = true
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}
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}
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runtime.SetFinalizer(f.file, (*file).close)
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return f
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}
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// Auxiliary information if the File describes a directory
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type dirInfo struct {
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buf []byte // buffer for directory I/O
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dir *syscall.DIR // from opendir
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}
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// epipecheck raises SIGPIPE if we get an EPIPE error on standard
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// output or standard error. See the SIGPIPE docs in os/signal, and
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// issue 11845.
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func epipecheck(file *File, e error) {
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if e == syscall.EPIPE && file.stdoutOrErr {
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sigpipe()
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}
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}
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// DevNull is the name of the operating system's ``null device.''
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// On Unix-like systems, it is "/dev/null"; on Windows, "NUL".
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const DevNull = "/dev/null"
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// openFileNolog is the Unix implementation of OpenFile.
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func openFileNolog(name string, flag int, perm FileMode) (*File, error) {
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chmod := false
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if !supportsCreateWithStickyBit && flag&O_CREATE != 0 && perm&ModeSticky != 0 {
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if _, err := Stat(name); IsNotExist(err) {
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chmod = true
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}
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}
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var r int
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for {
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var e error
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r, e = syscall.Open(name, flag|syscall.O_CLOEXEC, syscallMode(perm))
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if e == nil {
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break
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}
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// On OS X, sigaction(2) doesn't guarantee that SA_RESTART will cause
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// open(2) to be restarted for regular files. This is easy to reproduce on
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// fuse file systems (see http://golang.org/issue/11180).
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if runtime.GOOS == "darwin" && e == syscall.EINTR {
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continue
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}
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return nil, &PathError{"open", name, e}
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}
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// open(2) itself won't handle the sticky bit on *BSD and Solaris
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if chmod {
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Chmod(name, perm)
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}
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// There's a race here with fork/exec, which we are
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// content to live with. See ../syscall/exec_unix.go.
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if !supportsCloseOnExec {
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syscall.CloseOnExec(r)
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}
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return newFile(uintptr(r), name, kindOpenFile), nil
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}
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// Close closes the File, rendering it unusable for I/O.
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// It returns an error, if any.
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func (f *File) Close() error {
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if f == nil {
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return ErrInvalid
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}
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return f.file.close()
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}
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func (file *file) close() error {
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if file == nil {
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return syscall.EINVAL
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}
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var err error
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if e := file.pfd.Close(); e != nil {
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if e == poll.ErrFileClosing {
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e = ErrClosed
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}
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err = &PathError{"close", file.name, e}
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}
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if file.dirinfo != nil {
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syscall.Entersyscall()
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i := libc_closedir(file.dirinfo.dir)
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errno := syscall.GetErrno()
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syscall.Exitsyscall()
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file.dirinfo = nil
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if i < 0 && err == nil {
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err = &PathError{"closedir", file.name, errno}
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}
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}
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// no need for a finalizer anymore
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runtime.SetFinalizer(file, nil)
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return err
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}
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// read reads up to len(b) bytes from the File.
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// It returns the number of bytes read and an error, if any.
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func (f *File) read(b []byte) (n int, err error) {
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n, err = f.pfd.Read(b)
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runtime.KeepAlive(f)
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return n, err
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}
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// pread reads len(b) bytes from the File starting at byte offset off.
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// It returns the number of bytes read and the error, if any.
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// EOF is signaled by a zero count with err set to nil.
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func (f *File) pread(b []byte, off int64) (n int, err error) {
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n, err = f.pfd.Pread(b, off)
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runtime.KeepAlive(f)
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return n, err
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}
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// write writes len(b) bytes to the File.
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// It returns the number of bytes written and an error, if any.
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func (f *File) write(b []byte) (n int, err error) {
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n, err = f.pfd.Write(b)
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runtime.KeepAlive(f)
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return n, err
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}
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// pwrite writes len(b) bytes to the File starting at byte offset off.
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// It returns the number of bytes written and an error, if any.
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func (f *File) pwrite(b []byte, off int64) (n int, err error) {
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n, err = f.pfd.Pwrite(b, off)
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runtime.KeepAlive(f)
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return n, err
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}
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// seek sets the offset for the next Read or Write on file to offset, interpreted
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// according to whence: 0 means relative to the origin of the file, 1 means
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// relative to the current offset, and 2 means relative to the end.
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// It returns the new offset and an error, if any.
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func (f *File) seek(offset int64, whence int) (ret int64, err error) {
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ret, err = f.pfd.Seek(offset, whence)
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runtime.KeepAlive(f)
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return ret, err
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}
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// Truncate changes the size of the named file.
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// If the file is a symbolic link, it changes the size of the link's target.
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// If there is an error, it will be of type *PathError.
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func Truncate(name string, size int64) error {
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if e := syscall.Truncate(name, size); e != nil {
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return &PathError{"truncate", name, e}
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}
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return nil
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}
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// Remove removes the named file or directory.
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// If there is an error, it will be of type *PathError.
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func Remove(name string) error {
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// System call interface forces us to know
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// whether name is a file or directory.
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// Try both: it is cheaper on average than
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// doing a Stat plus the right one.
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e := syscall.Unlink(name)
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if e == nil {
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return nil
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}
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e1 := syscall.Rmdir(name)
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if e1 == nil {
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return nil
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}
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// Both failed: figure out which error to return.
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// OS X and Linux differ on whether unlink(dir)
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// returns EISDIR, so can't use that. However,
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// both agree that rmdir(file) returns ENOTDIR,
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// so we can use that to decide which error is real.
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// Rmdir might also return ENOTDIR if given a bad
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// file path, like /etc/passwd/foo, but in that case,
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// both errors will be ENOTDIR, so it's okay to
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// use the error from unlink.
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if e1 != syscall.ENOTDIR {
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e = e1
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}
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return &PathError{"remove", name, e}
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}
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func tempDir() string {
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dir := Getenv("TMPDIR")
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if dir == "" {
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if runtime.GOOS == "android" {
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dir = "/data/local/tmp"
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} else {
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dir = "/tmp"
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}
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}
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return dir
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}
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// Link creates newname as a hard link to the oldname file.
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// If there is an error, it will be of type *LinkError.
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func Link(oldname, newname string) error {
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e := syscall.Link(oldname, newname)
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if e != nil {
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return &LinkError{"link", oldname, newname, e}
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}
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return nil
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}
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// Symlink creates newname as a symbolic link to oldname.
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// If there is an error, it will be of type *LinkError.
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func Symlink(oldname, newname string) error {
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e := syscall.Symlink(oldname, newname)
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if e != nil {
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return &LinkError{"symlink", oldname, newname, e}
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}
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return nil
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}
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